Inventive Step: How high is the obviousness threshold?

As part of the long running legal battle in Australia concerning the validity (and infringement) of a series of second generation patents in respect of the cholesterol lowering drug rosuvastatin (Crestor®), the High Court of Australia is set to refine the threshold of the inventive step required in Australia for a patentable invention.

The issue for determination by the High Court is what is the "starting point" for the consideration of inventive step - is it what the patentee had to hand (as disclosed in the patent specification) or the accepted common general knowledge ("CGK")?

The pending decision is important as it will clarify the approach in Australia to assessing the obviousness of a method of treatment in the pharmaceutical space. It will clarify if the specification and the identification of the problem in the specification is the correct starting point for the obviousness question, and what the correct process is to apply in using multiple sources of prior art information in determining inventive step.

In this case, at issue is AstraZeneca’s Australian patent for a method of treating patients with high blood cholesterol using the compound rosuvastatin by administering a claimed low dose of the active ingredient. The compound was never the subject of a patent in Australia.

The relevant test for validity to be applied in Australia is that a claimed invention will involve an inventive step when compared to the prior art unless it would have been obvious to a person skilled in the relevant art in the light of the common general knowledge, alone or together with a single piece of prior art information (or more than one where they would have been considered a single source of information) ascertained, understood and regarded as relevant.

The judge at first instance found the claimed invention obvious in light of the common general knowledge alone (without any prior art documents). In reaching this finding, Her Honour had found that the patent specification identified the invention in a manner that pre-supposed the existence of rosuvastatin and that the invention involved nothing more than the selection of a dosage range for rosuvastatin which was obvious in light of the CGK.

On appeal, the Full Federal Court found it incorrect to attribute knowledge of the problem on the basis of the inventor's "starting point" gleaned from the specification as a whole where the problem was not common general knowledge. In other words, what constitutes common general knowledge must be determined objectively by reference to what is actually known and available in the relevant field. Accordingly, the appeal court held that knowledge of rosuvastatin could not be the starting point from which to consider inventive step.

Nevertheless, the appeal court still found the patent to be obvious in light of the common general knowledge together with either of two publications ("Watanabe" or the "471 Patent").

In oral argument before the High Court, it is common ground that, in solving the problem (the need for a more efficacious statin), a search for material that is not in the common general knowledge would be undertaken.

Relevantly, the evidence in this case was that "Watanabe" and the "471 Patent" were two of 19 document abstracts which were ascertained and selected from over 4000 abstracts for review of the full article. The evidence in the case relied upon to establish lack of inventive step was that the skilled addressee relied upon a publication (not being relevant prior art for the question of inventive step), to teach the relevance of the Watanabe publication.

The Full Federal Court said that a "skilled person, notionally knows nothing beyond the common general knowledge…. It is…wholly within the scheme of the subsection that he or she might well sort through all manner of information with a view to finding something that is "regarded as relevant". There is nothing in the provision which would place an embargo upon the skilled person using combinations of sources of information along the road to that destination". The Court went on to find that the skilled person, either "armed" with the Watanabe article or the 471 Patent, would be "armed" with rosuvastatin, and that the only issue that then arose would be whether they would be directly led as a matter of course to try the dosage claimed in the Patent.

On appeal to the High Court, AstraZeneca has argued that the Full Federal Court erred in construing the Patents Act so as to permit a comparison of prior art information from multiple sources obtained by the skilled addressee on the path to determining whether any given prior art document was "relevant". It is asserted that this is the gravamen of the approach endorsed by the Court in allowing the Watanabe article or the 471 Patent to be considered as relevant prior art information to assess inventive step.

Recent amendments to the Patents Act (applicable to patents from applications filed since April 2013 or in respect of which examination has been requested since that date) have removed the requirement that prior art information used to assess inventive step must be "ascertained, understood and regarded as relevant" by the skilled addressee. This means that if this patent was considered under the new provisions, the Court could find that the key prior art publications were relevant (without their "ascertainment" being in issue).

However, the High Court's decision will be very relevant to patents in dispute under the pre 2013 Patents Act.

The High Court's decision is expected to be delivered in the second half of this year.